1. Field of the Invention
This invention relates to a drive shaft that is turned by the wind and the rotary power of which can be utilized for a variety of purposes, such as to drive a hydraulic pump, the crankshaft for a water pump, or an electrical generator.
2. Description of the Related Art
A number of patents have been issued for devices which have only one vane on each of several arms that are designed to provide rotary motion to a central shaft when the vane on or more arms intercepts the wind. These include U.S. pat. No. 2,247,929; U.S. pat. No. 4,115,027; U.S. pat. No. 4,203,707; and U.S. pat. No. 4,818,180. Of these patents, only U.S. Pat. No. 4,203,707 provides structural support for the outer portion of the arm beyond that created by the arm, itself; and U.S. Pat. No. 4,203,707 requires a bearing both on the top and the bottom of the central shaft in order to create such support. (U.S. Pat. No. 2,247,929 also employs a bearing both near the top and the bottom of the central shaft but does not thereby generate support for the outer portion of the arm.)
Moreover, U.S. Pat. No. 4,115,027 employs an airfoil rather than just a vane, which is substantially planar, to intercept the wind; and the vane of U.S. Pat. No. 4,818,180 rotates about a horizontal axis so that the weight of the vane would cause it to drop, creating forces from the wind on both sides of the central shaft so that the resultant rotary force is reduced.
Patents which apply to multiple vanes on each of several arms that are designed to provide rotary motion to a central shaft when the vanes on one or more arms intercepts the wind are Danish U.S. Pat. No. 29377; U.S. Pat. No. 4,496,283; U.S. Pat. No. 4,534,703; U.S. Pat. No. 5,256,034; and U.S. Pat. No. 5,266,006.
Of this latter category of patents, only patent no. 4,534,703 has a provision for providing structural support for the outer portion of the arm beyond that created by the arm, itself; and U.S. Pat. No. 4,534,703 does so by placing wheels near the outer end of the arm to roll on a substantially horizontal surface.
Moreover, U.S. Pat. Nos. 4,496,283 and 5,266,006 utilize bearings near the top and bottom of the central shaft that do not provide support for the outer portion of the arm.
None of the preceding patents, however, utilize two or more bearings along the central shaft, all of such bearing being on the same side of the arms, to stabilize the central shaft.
Within the category of patents each of whose arms support more than one vane, only U.S. Pat. Nos. 4,534,703 and 5,256,034 mechanically coordinate the movement of all vanes (or, in the case of U.S. Pat. No. 5,256,034, airfoils) on a given arm. (Although not explicitly recognized in either patent, such coordination precludes adjacent vanes from becoming entangled with one another. In fact, U.S. Pat. No. 5,256,034 declares that the purpose for the coordination is to cause the airfoils to be "orientable to take maximum advantage of the wind flowing pat the device.") U.S. Pat. No. 4,534,703, however, also mechanically coordinates the movement of vane on opposite sides of the central shaft; if the direction of the wind along the rather substantial length of both arms is not uniform, this coordination will cause some vanes to be in a position that reduces the total rotational force that is generated and is unnecessary for avoiding entanglement of vanes because the vanes on opposite arms could not become entangled with one another. Additionally, U.S. Pat. No. 5,256,034 has the mechanical mechanism which provides the coordination attached to the airfoils.
And the only patents discussed above which indicate the type of material from which the vanes can be made are U.S. Pat. Nos. 2,247,929 and 4,496,283. On lines 18 through 20 of column 2, U.S. Pat. No. 2,274,929 states, "The vanes 26 consist preferably of sheet metal, but other suitable material may be employed." And in lines 45 through 46 of column 2, U.S. Pat. No. 4,496,283 observes that the vents "may be made of a solid rigid material such as sheet metal or plastic." None of the preceding patent, though, notes that plastic or fiberglass is not strong enough and that metal and aluminum strike the frame with such momentum that the vanes destroy the structure whereas a light but strong material such as PLEXIGLAS has sufficient strength to withstand the force of the wind with sufficiently low momentum that the frame is usually not even struck by the vanes but would not be damaged if such a collision did occur.